Etymology

The etymology of Carn Dûm is uncertain. Concerning the real world languages, it could be Gaelic, in which it roughly translates as "mountain fortress";[1] although Tolkien uses Celtic elements for some translated Mannish names, this would have been the only instance where he uses Gaelic. It is unknown whether this is just coincidence or not.

Though Sindarin in form and sound, neither words carn and dûm have been attested in Sindarin. Carn could be a form of caran, "red" possibly also seen in "Carcharoth", "red maw".